Biology is the study of living organisms, divided into many specialized fields that cover their morphology, physiology, anatomy, behavior, origin, and distribution.
This is basically the definition of biology, so you may need to add a little more detail. This is a great way to get it started though!!!
Hope this helps!!
The answer is False.
Although, there are some evidence that suggests that species from million years ago possessed both gills and lungs. For example is the Acanthostega Gunnari, one of the oldest species discovered with four limbs. The creature is a salamander-like creature found in Greenland hundreds of million years ago. Although the specie can walk on land but the finding characterized the creature primarily as a fish.
Probability is the measure of the likeliness that an event will occur. So.. probability.